Emond Papegaaij ( https://hibernate.atlassian.net/secure/ViewProfile.jspa?accountId=557058%... ) *created* an issue Hibernate ORM ( https://hibernate.atlassian.net/browse/HHH?atlOrigin=eyJpIjoiYTRjZTcyNDIw... ) / Bug ( https://hibernate.atlassian.net/browse/HHH-16471?atlOrigin=eyJpIjoiYTRjZT... ) HHH-16471 ( https://hibernate.atlassian.net/browse/HHH-16471?atlOrigin=eyJpIjoiYTRjZT... ) Entities serialized in QueryKey ( https://hibernate.atlassian.net/browse/HHH-16471?atlOrigin=eyJpIjoiYTRjZT... ) Issue Type: Bug Affects Versions: 6.2.0 Assignee: Unassigned Components: hibernate-core Created: 14/Apr/2023 01:28 AM Priority: Major Reporter: Emond Papegaaij ( https://hibernate.atlassian.net/secure/ViewProfile.jspa?accountId=557058%... ) This seems to be a regression introduced by https://hibernate.atlassian.net/browse/HHH-16281. When an entity is used on the root of a cacheable (sub)query, this entity gets serialized into the QueryKey. In our case this breaks hard because our entities do not implement Serializable , but I doubt it the cache entry would be any good if the entity were to implement Serializable. The attached testcase demonstrates the problem and fails with the following exception: java.lang.ClassCastException: class org.hibernate.bugs.entities.MyEntity2 cannot be cast to class java.io.Serializable (org.hibernate.bugs.entities.MyEntity2 is in unnamed module of loader 'app'; java.io.Serializable is in module java.base of loader 'bootstrap') at org.hibernate.type.descriptor.java.ImmutableMutabilityPlan.disassemble(ImmutableMutabilityPlan.java:43) at org.hibernate.metamodel.mapping.BasicValuedMapping.addToCacheKey(BasicValuedMapping.java:71) at org.hibernate.metamodel.mapping.internal.BasicEntityIdentifierMappingImpl.addToCacheKey(BasicEntityIdentifierMappingImpl.java:388) at org.hibernate.query.internal.QueryParameterBindingsImpl.generateQueryKeyMemento(QueryParameterBindingsImpl.java:184) at org.hibernate.cache.spi.QueryKey.from(QueryKey.java:54) at org.hibernate.sql.exec.internal.JdbcSelectExecutorStandardImpl.resolveJdbcValuesSource(JdbcSelectExecutorStandardImpl.java:422) at org.hibernate.sql.exec.internal.JdbcSelectExecutorStandardImpl.doExecuteQuery(JdbcSelectExecutorStandardImpl.java:267) at org.hibernate.sql.exec.internal.JdbcSelectExecutorStandardImpl.executeQuery(JdbcSelectExecutorStandardImpl.java:168) at org.hibernate.sql.exec.internal.JdbcSelectExecutorStandardImpl.list(JdbcSelectExecutorStandardImpl.java:93) at org.hibernate.sql.exec.spi.JdbcSelectExecutor.list(JdbcSelectExecutor.java:31) at org.hibernate.query.sqm.internal.ConcreteSqmSelectQueryPlan.lambda$new$0(ConcreteSqmSelectQueryPlan.java:109) at org.hibernate.query.sqm.internal.ConcreteSqmSelectQueryPlan.withCacheableSqmInterpretation(ConcreteSqmSelectQueryPlan.java:302) at org.hibernate.query.sqm.internal.ConcreteSqmSelectQueryPlan.performList(ConcreteSqmSelectQueryPlan.java:243) at org.hibernate.query.sqm.internal.QuerySqmImpl.doList(QuerySqmImpl.java:521) at org.hibernate.query.spi.AbstractSelectionQuery.list(AbstractSelectionQuery.java:367) at org.hibernate.query.sqm.internal.QuerySqmImpl.list(QuerySqmImpl.java:1084) at org.hibernate.query.Query.getResultList(Query.java:119) at org.hibernate.bugs.JPAUnitTestCase.hhh16025Test(JPAUnitTestCase.java:55) ( https://hibernate.atlassian.net/browse/HHH-16471#add-comment?atlOrigin=ey... ) Add Comment ( https://hibernate.atlassian.net/browse/HHH-16471#add-comment?atlOrigin=ey... ) Get Jira notifications on your phone! Download the Jira Cloud app for Android ( https://play.google.com/store/apps/details?id=com.atlassian.android.jira.... ) or iOS ( https://itunes.apple.com/app/apple-store/id1006972087?pt=696495&ct=Em... ) This message was sent by Atlassian Jira (v1001.0.0-SNAPSHOT#100221- sha1:8830b7c )